Atlanta Falcons offensive coordinator Kyle Shanahan celebrates with Matt Ryan #2 after defeating the Green Bay Packers in the NFC Championship Game at the Georgia Dome on January 22, 2017 in Atlanta, Georgia. The Falcons defeated the Packers 44-21. (Kevin C. Cox/Getty Images)

Atlanta Falcons quarterback Matt Ryan (2) speaks with offensive coordinator Kyle Shanahan before the first half of an NFL football game between the Atlanta Falcons and the Kansas City Chiefs, Sunday, Dec. 4, 2016, in Atlanta. (AP Photo/John Bazemore)

Cleveland Browns offensive coordinator Kyle Shanahan, center, talks with quarterbacks Brian Hoyer (6) and Johnny Manziel on the bench in the third quarter of an NFL football game Sunday, Nov. 2, 2014, in Cleveland. (AP Photo/David Richard)

Cleveland Browns offensive coordinator Kyle Shanahan looks over his play sheet during an NFL football game against the Oakland Raiders in Cleveland on Oct. 26, 2014. (AP Photo/Tony Dejak, File)

Cleveland Browns quarterback Johnny Manziel (2) listens in as offensive coordinator Kyle Shanahan, center, talks with quarterback Brian Hoyer (6) on the sidelines in the fourth quarter of a preseason NFL football game against the St. Louis Rams in Cleveland on Aug. 23, 2014. (AP Photo/David Richard)

Evan Vucci/AP Photo

Cleveland Browns quarterback Brian Hoyer (6) talks with offensive coordinator Kyle Shanahan during the first half of an NFL preseason football game against the Washington Redskins Monday, Aug. 18, 2014, in Landover, Md. (AP Photo/Evan Vucci)

Washington Redskins quarterback Robert Griffin III talks with offensive coordinator Kyle Shanahan before a NFL football game against the San Diego Chargers in Landover, Md., Sunday, Nov. 3, 2013. (AP Photo/Alex Brandon)

Washington Redskins quarterback Robert Griffin III works a drill with offensive coordinator Kyle Shanahan behind, during warm ups on Aug. 19, 2013 before a game against the Pittsburgh Steelers in Landover, Md. (AP Photo/Nick Wass)

Houston Texans quarterback Matt Schaub (8) laughs with QB coach Kyle Shanahan, right before an NFL football game against the New England Patriots Sunday, Jan. 3, 2010 in Houston. The Texans won 34-27 for their first winning season.(AP Photo/Dave Einsel)

“He loved being around,” said Gary Plummer, a linebacker on that team. “Keeping footballs dry at practice, always hustling. Paying attention to everything. Being seen and not heard. His dad taught him well.”

That boy is expected to to be introduced as The Man this week when Shanahan, 37, is formally announced as the 20th head coach in 49ers history.

It’s not quite the triumphant homecoming it could have been. On the verge of a Super Bowl victory Sunday, the Atlanta Falcons let the New England Patriots roar back for 34-28 overtime victory. Shanahan, the Falcons’ offensive coordinator, was the one who left the gate open.

With about 5 minutes to play, Atlanta receiver Julio Jones hauled in a pass at the Patriots’ 22-yard line. This is where a few boring play-calls would have served the Falcons well. Three safe running plays and a 40-yard field goal would have put them ahead 31-20. Instead, Shanahan called for Matt Ryan to pass on second down — and the resulting sack set off a calamitous chain of events. No less an authority than Young, the Hall of Famer, called the Falcons’ fourth-quarter play-calling “inexcusable” on the ESPN postgame show.

But Ryan stood by his outgoing coordinator.

“Too aggressive? No,” the NFL MVP said. “No, I thought Kyle did a good job. We played the way that we play. We always play aggressive and we play to win.”

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Even amid the second guessing, the 49ers had no second thoughts about their presumptive head coach. After all, the Falcons led the NFL with 33.8 points per game during the regular season. And the 49ers don’t mind that their new coach comes with some swagger: Shanahan’s task is nothing less than lifting a fallen dynasty out of the smoldering ash.

“I thought he was the catch of this head coaching cycle,” John Lynch said upon being name the 49ers’ new general manager last week. “I think it’s one of the best years I’ve seen a coordinator have. When I talked to Matt Ryan and the other players, they spoke of the leadership and the presence that Kyle had in front of that room.”

The first thing to establish about Shanahan as a head coach is that he always wanted to be one. There’s a reason he made a habit of tagging along with dad to work. Mike Shanahan was the 49ers’ offensive coordinator from 1992-94 and later won two Super Bowls as the Denver Broncos’ head coach.

Kyle knew his path to the NFL involved a whistle and a clipboard, even as a college player. Mack Brown, the former Texas head coach, recalled the day he got an unusual request from his old friend. Brown and Mike Shanahan had started their coaching careers about the same time and gotten to know each other at clinics and conventions over the years.

“Mike calls me up one day and says, ‘Kyle really wants to coach. He wants to really learn the ropes. Can he come out and play for you at Texas?’ ” Brown recalled.

“I said sure. I thought I was doing Mike a favor. … But he wound up being a starter for us.”

Kyle Shanahan transferred from Duke and spent two seasons playing for the Longhorns. His entire statistical output — 14 catches for 127 yards — represented about day’s work for Julio Jones.

But the receiver left an impression on Brown with the way he grabbed concepts.

“From Day 1, he was a coach’s kid, a gym rat,” he said. “If you wanted a 7-yard route, he would run exactly a 7-yard route.

“He was a fun player. He’d laugh, cut up and be loose. But when the game started, he was as competitive as any guy we’ve ever had.”

Kyle Shanahan’s head start in his profession served him well. He moved up the ladder quickly. It helped that he had a knack for catching on with other Super Bowl-winning coaches besides the one in his own household.

Shanahan was a low-level offensive quality control coach under Jon Gruden with the Tampa Bay Buccaneers before handling several roles for Gary Kubiak with the Houston Texans. He spent his first season in Houston as the receivers coach and his second as a quarterbacks coach before being promoted to play caller.

Kyle’s ascent took place at a record pace: He was the youngest offensive coordinator in NFL history in 2008, when the Texans gave him the job at 28 years, 26 days.

But he still had some growing up to do.

That took place the hard way, during a rocky — if formative — stint with Washington. Mike hired Kyle to be his offensive coordinator there, but this father/son pairing was no picnic.

Donovan McNabb, the quarterback for the 2010 Washington team, can laugh about those days now. But he recalled in a phone interview how he clashed with Kyle Shanahan in both style and substance.

It was a volatile mix: McNabb made six Pro Bowls while with the Philadelphia Eagles and arrived in Washington with strong feelings about what schemes worked best for him. Shanahan was a young and cocky play caller, not to mention the boss’ son.

“We both had our egos,” said McNabb, who set a career high with 15 interceptions in his lone season in Washington. “There was no sitting down and discussing what we were going to do to make it easier for every party going forward.”

Terrell Davis, newly minted last week as a Hall of Fame running back, had an unusual vantage point for that simmering feud. Davis, who played for Mike Shanahan in Denver, followed him to Washington for a short coaching internship. He watched as Kyle Shanahan kept trying to get McNabb to roll out wider on his bootlegs; the quarterback kept pulling up short.

One day, the coordinator finally snapped.

“Kyle went off like I’ve never seen before,” said Davis, now an analyst for the NFL Network. “I’d never seen him talk like that. After the meeting, he had some second thoughts. He said, ‘Dude, should I have done that?’ I said, ‘Absolutely you should have.’

“That was kind of him growing up a little bit. He was becoming a coach and a leader. He was learning how to get the most of players.”
Quarterback Donovan McNabb and offensive coordinator Kyle Shanahan rarely saw eye to eye when the two were with the Washington Redskins. (AP Photo/Carolyn Kaster)

The Shanahans were fired after the 2013 season in part because of Washington’s 3-13 record and last-place finish, but also because of their strained relationship with quarterback Robert Griffin III, who also didn’t see eye-to-eye with the father-son duo.

McNabb, having watched Shanahan’s evolution since those days, said it has been encouraging to watch the coordinator now handle his differences with more diplomacy. Just one season ago, there were rumblings of a rift between Ryan and Shanahan. But the two made a point of addressing things in the offseason and hammered out their differences over a couple of beers.

Ryan rebounded with a career-best season as Atlanta led the NFL with 540 points. Ryan led the NFL with a franchise-record 117.1 passer rating.

“It’s a total turnaround,” said McNabb, now a basketball analyst for the beIN Sports Network. “You see what happened last year: People were questioning Matt Ryan and whether he was an elite quarterback. But a lot of it was miscommunication between him and Kyle. And you could see that throughout the whole season.

“I think one thing that Kyle’s done is that he’s put his ego to the side and kind of focused on a little bit more on the strengths of his quarterback.”

The result is a coach whose leadership skills seem as adaptable as his playbook, which is saying something. The Falcons set a record during the regular season by completing touchdown passes to 13 different receivers.

Atlanta was so balanced in its running and passing attacks that Shanahan knew he could keep teams guessing. The Falcons used play-action on 26 percent of their offensive plays, more than any NFL team, according to Football Outsiders.

“He’s getting mismatches with the tight end, running backs, the wings. He’s way ahead of the game. I’m really, really proud,” said Brown, his old college coach.

“I saw one of those highlight shows the other night where somebody broke down their offense for 15 minutes and showed why the Falcons were giving people problems. I was very, very impressed with his formations.”

Such wrinkles have long been missing from the 49ers, who haven’t ranked in the league’s top 10 for offense since 2003. But they were humming back in Mike Shanahan’s day, when the offensive coordinator was so relentlessly detail-oriented that Steve Young called him, “Let’s Go Over It Again Shanahan.”

Now, they will be counting Kyle Shanahan to be a chip off the old blocking sled.

“He’s not riding his dad’s coattails anymore, and that’s served him well,” Davis said. “He’s not some young guy. No, he’s earned that respect.”